You can find the Color and Typography settings through the settings interface.
Start by clicking the Settings tab at the top of the dashboard. This will open the interface with many subsections for the user to edit and change to their own fit.
From here, Click the Magazine section located to the left side of the dashboard, underneath General and all of its subsections. Then click on the Interface Colors and Typography link under the Magazine section. The interface for changing the Publication navigation interface for the colors and typography will then be displayed.
Go through each setting for both color and typography and change the settings to which you see fit. Once you have chosen the settings you are happy with, make sure to click the green Save Settings button next to the interface title at the top.
The Interface when viewing the magazine will then use the settings you have changed, this applies to all users viewing the magazine.